Impulse sender for the drive of timing devices, preferably automatic permanent calendars



3,3 78,693 PBEPERABLY April 16, 1968 K. w. SCHMIDT DER FOR THE DRIVE OF TIMING DEVICES IMPULSE SEN AUTOMATIC PERMANENT CALENDARS 2 Sheets-Sheet- 1.

FIG. 2.

E PRIOR ART INVENTOR. KARL WILHELM SCHMIDT ATTORNEY.

April 16, 1968 w. sc mT 3,378,693,

IMPULSE SBNDER FOR THE DRIVE OF TIMING DEVICES, PREFERABLY AUTOMATIC PERMANENT CALENDARS Filed July 21, 1965 2 Sheets-Sheet. L

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-- ,C' T NPN INVENTOR. KARL WILHELM SCHMIDT BY F ATTORNEY.

United States Patent 3,378,693 IMPULSE SENDER FOR THE DRIVE 0F TIMING DEVICES, PREFERABLY AUTOMATIC PERMA- NENT CALENDARS Karl Wilhelm Schmidt, Idar-Oberstein, Germany, assignor to Firma Gebruder Schmidt Metallwarenfabrik, Idar- Oberstein, Germany, a corporation of Germany Filed July 21, 1965, Ser. No. 473,799 Claims priority, application Germany, July 25, 1964, Sch 35,527 4 Claims. (Cl. 307-132) The present invention relates to an impulse sender for the drive of timing devices, preferably automatic permanent calendars and is concerned with the improvement of the known multivibrator circuit with complementary transistors.

It is known that great pulse duty factors can be obtained, for example 1:l0,000 with such circuits. It is also known that impulse duration and impulse spacing depend comparatively little upon the supply voltage. For non-stabilized, battery-operated time-indicators the known circuits can hardly be used, nevertheless. Upon lowering of the battery voltage, the impulse spacing is getting shorter and consequently, the time indication is not exact.

This effect is caused by the rising of the inner resistance of an aging battery. A stabilization of the source of current by, for instance, a Zener diode cannot be tolerated, due to the continuous current consumption of such arrangement.

It is, therefore, one object of the present invention to provide an impulse sender for the drive of timing devices, preferably automatic permanent calendars, wherein the battery with its variable inner resistance is separated from the time indicator during the impulse duration and the time indicator is driven by a condenser charged during the impulse spacing. By this arrangement, the time indicator is independent from the inner resistance of the battery.

With this and other objects in view which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:

FIGURE 1 is a circuit diagram of a conventional multivibrator circuit;

FIG. 2 is a circuit diagram of a revised multivibrator circuit designed in accordance with the present invention;

FIG. 3 is another embodiment of the circuit diagram disclosed in FIG. 2;

FIG. 4 is still another embodiment of the circuit diagram disclosed in FIG. 2;

FIG. 5 is a schematic perspective view of a mechanical drive of the time indicator;

FIG. 6 is a schematic perspective view of a stepwise operated motor with a switching amplifier;

FIG. 7 is a schematic perspective view of a step-switching device for operation by means of a working contact of a relay;

FIG. 8 is a part of the circuit disclosing the flow of current during the impulse duration; and

FIG. 9 is a part of the circuit disclosing the flow of current during the impulse spacing.

Referring now to the drawings and in particular to FIG. 1, the impulse sender comprises a multivibrator circuit, known in the prior art, wherein a battery 1 charges a resistance R over the emitter-collector conductance of the transistor T and the base-emitter conductance of the transistor T charges the condenser C. Upon enlarging the resistance R, the impulse duration becomes longer, how ever, the impulse spacing becomes appreciably much shorter. In an aging battery the increasing inner resistance is added to the resistance R during the impulse duration. Due to this fact, the frequency of the impulses increases.

A stabilization of the source of current by, for instance, a Zener diode, is prohibitive, due to the continuous current consumption of such arrangement.

Referring now again to the drawings and in particular to FIG. 2, a circuit is disclosed in which the battery 1' with its variable inner resistance is separated from the time indicator during the impulse duration, and the time indicator is driven by the condenser C charged during the impulse spacing.

Thus, the condenser C is charged over the outer resistance R and the diode D during the impulse spacing. It now the multivibrator switches over, the transistor T is connected through. The battery voltage is in operative connection with R The collector of the transistor T is rendered positive. By this arrangement the diode D switches off the condenser C from the battery voltage. The charge of the condenser C takes place over the emitter-collector conductance of the transistor T and the resistances NTC, R and R on the one hand, and over the base-emitter conductance of the transistor T by the condenser C on the other hand.

The battery 1' feeds now merely the outer resistance R,,, while the members R NTC, R C R and R are fed from the condenser C Such arrangement, if operated, for example, with a frequency of one impulse per minute, as a clock, results in a deviation of less than one minute per day.

Referring now again to the drawings and in particular to FIG. 3, another embodiment of the circuit is disclosed, in which for the purpose of economy the diode D is replaced by a relay R which is formed as a break contact and separates the voltage source from the condenser C during the impulse duration. Thus, the time condenser C, can be charged from the condenser C only.

Electronic or mechanical switches can be replaced also by an ohmic resistance, which is to be dimensioned such that the discharge of the feeding condenser C through this ohmic resistance is small during the impulse duration relative to the discharge of the feeding condenser C to the time condenser C Referring now again to the drawings and in particular to FIG. 4, a circuit including such ohmic resistance R is disclosed. In order to maintain as small as possible the influence of the ohmic resistance R and of the condenser C upon the time element, it is required to charge extensively the condenser C during the impulse spacing. For this reason, the time constant for the charge of the condenser C should be shorter than that of the members C R and R While in the circuit disclosed in FIG. 2 a diode D has been shown as a switch, it is to be understood that the diode D can be replaced by a transistor, in spite of the greater expense, a four-layered diode or a controllable rectifier, as a silicium rectifier. It should be further emphasized that R can constitute a relay for the impulses or a particular outer resistance. The transistor T of the time indicator can constitute either a relay for the direct mechanical drive of the step-by-step switch, as indicated in FIG. 3 of the drawings, or an ohmic outer resistance to operate as a switching amplifier for a larger output. In case of the use of a relay with two switching contacts, one of the switching contacts is used as a make contact for a drive of greater output and the other of the switching contacts is used as a break contact for separating the condenser C from the source of current.

NTC is a resistance having a negative temperature coetficient, while the resistance R, is a linearizing resistance for the temperature curve of this resistance and serves the adjustment of the temperature condition of the multivibrator. The exact dimensions depend upon the used parts, as transistors and condensers.

FIG. 5 discloses an application of the device, designed in accordance with the present invention, wherein the relay R,, of FIGS. 1 to 4 for the direct mechanical drive of a gear 2 of a time indicator (not shown), meshing with a pawl 3 which is operated by a pivoted armature 4 of the relay R is disclosed.

FIG. 6 discloses another application of the device, wherein a step-by-step motor 5 is operated by the relay R over a switch amplifier.

FIG. 7 discloses still another application of the device, wherein a step-by-step switch is operated by a make contact 6 of the relay R while a break contact 7 is used for separation of the condenser C The adjustable resistance NTC must be dimensioned such that the desired time interval can easily be preset, as an upper limit thereof, and the tolerances of the structural elements can still be balanced, as a lower limit thereof. Any inner resistances of the P and N transistors are balanced out roughly by the corresponding election of the resistance R; and finely by the variable resistance R The dimensions of the respective elements disclosed in FIGS. 1 to 4 are given, by example, for impulse spacing of one minute.

FIG. 8 indicates quite clearly the current flow during the impulse duration showing the charging of the condenser C from the condenser C while FIG. 9 indicates the current flow during the impulse spacing disclosing the discharging of the time condenser C over the resistances R and R and the charging of the condenser C by means of the switch S.

While I have disclosed several embodiments of the present invention, it is to be understood that these embodiments are given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

4 I claim: 1. An impulse sender for the drive of timing devices, comprising a multivibrator including a voltage source and an outer resistance disposed in series,

a condenser disposed in parallel with said voltage source and said resistance and charged from said voltage source during the impulse spacing,

a time condenser disposed in parallel with said voltage source and said outer resistance, and

switching means disposed in series with said condenser for separating said condenser from said voltage source during the impulse duration, and charging said time condenser from said condenser.

2. The impulse sender, as set forth in claim 1, wherein said switching means comprises an electronic switch.

3. The impulse sender, as set forth in claim 1, wherein said switching means comprises a makeand breakcontact.

4. The impulse sender, as set forth in claim 1, wherein said switching means comprises a resistance of predetermined value.

References Cited UNITED STATES PATENTS 2,735,009 2/1956 Harry 307-132 X 2,752,511 6/1956 Beaufoy 307132 3,074,028 1/1963 Mammano 331-111 3,306,030 2/1967 Wiley 331111 X 3,329,907 7/1967 Helgeson et al 331--111 ORIS L. RADER, Primary Examiner.

T. B. JOIKE, Assistant Examiner. 

1. AN IMPULSE SENDER FOR THE DRIVE OF TIMING DEVICES, COMPRISING A MULTIVIBRATOR INCLUDING A VOLTAGE SOURCE AND AN OUTER RESISTANCE DISPOSED IN SERIES, A CONDENSER DISPOSED IN PARALLEL WITH SAID VOLTAGE SOURCE AND SAID RESISTANCE AND CHARGED FROM SAID VOLTAGE SOURCE DURING THE IMPULSE SPACING, A TIME CONDENSER DISPOSED IN PARALLEL WITH SAID VOLTAGE SOURCE AND SAID OUTER RESISTANCE, AND 